Research On Off-grid Wind Power System Based On Squirrel-cage Induction Generator

Recently, the grid-connected wind power system spring up interiorly. However, with theincreasing development many problems are exposed, such as long-distance transmission cost, thebackward at the power grid built, and the technology bottleneck. At the same time, the stand-alonewind power system has solved the basic electricity problems for many remote areas, since it begins in70s, and has already to take its place in urban areas such as landscape lighting in last several years.The traditional small wind power generation control system is simple, and its two main defects arelow energy utilization rate and short battery life.In order to solve these problems, this paper takes a5kW vertical-axis induction wind powergeneration system as the research object. The control system adopts energy management strategy, notonly realize the maximum wind power tracking, but also the battery charging and discharging. Theinduction generator uses slip frequency based control strategy, based on the relationship between slipfrequency and electromagnetic torque under certain conditions. The strategy makes the torquecontrolled directly, without any sophisticated coordinate transform, and also has good dynamic andstatic performance. The battery charging strategy is combined of the grading control and thecurrent-limiting control.The simulation model is constructed to verify the system control strategy. The simulation resultsdemonstrate that the MPPT control is realized effectively, the slip frequency based control strategydisplays good dynamic and steady performance, and also the battery is charged steadily.In order to further test the system, the software and hardware platform of control system aredesigned and realized. The experimental results demonstrate that the control method is feasible andcorrect. After that, a set of wind power generation control cabinet used in wind field is constructed.Large amounts of valid data are acquired through the automatic monitor, and compared with the datafrom another permanent magnet synchronous system under the same test environment. The resultsshow that, the induction generation system performs well in the actual wind power application field.Research results show that, the squirrel-cage induction generator system has wide applicationpotential and further research value, thus will be a competitive choice in the wind power generationfields.